1. Field of the Invention
The present invention relates to an optical sensor that can be used in a domestic washing machine or other laundry processing appliance. Particularly, the present invention relates to an optical sensor for measuring forces occurring in the appliance.
2. Description of the Prior Art
In the case of so-called top-loader washing machines, for example, an optical sensor can be used to measure forces exerted by a tub, suspended on a plurality of carrying rods in a machine housing, upon one of the carrying rods. Such force measurements may be used, for example, to deduce the quantity of laundry filled into the tub, its absorbency, its weight when wet, its weight when moist, and numerous other operating states of the machine. The range of application of the sensor is not limited, however, to the measurement of force in a laundry processing appliance. In principle, the sensor is available for any measurement applications in which changes in position of a first component, relative to a second component, are to be sensed by means of light (i.e. optically).
Known from DE 10 2010 013 386 A1, in combination with FIG. 4 therein, is an optical sensor, in which a reflective-surface carrier is coupled to a measuring rod and, by means of a helical spring, is biased into a neutral position relative to a sensor housing. The reflective-surface carrier provides two reflective surfaces, which are both irradiated by a light beam in an eccentrically offset manner in relation to a rod axis of the measuring rod. The intensity of the reflected radiation sensed by a detector varies according to an axial distance of the reflective-surface carrier from an element emitting the respective light beam.